Need to add class to first element in a foreach loop

Question

I'm pulling all attachments for this particular post and displaying them in a carousel. Problem is I need to give the first item a class of active so bootstrap carousel will work.

Here is my loop:

<?php foreach ( $attachments as $attachment ):
    $description = $attachment->post_content;
    echo '<div class="item" data-description="' . $description . '">';
    echo wp_get_attachment_image($attachment->ID, 'large');
    echo '</div>';
    endforeach;
?>

I've tried:

<?php $isFirst = true; ?>

<?php foreach ( $attachments as $attachment ):
    $description = $attachment->post_content;
    echo '<div class="item' . $isFirst ? ' active' : '' . '" data-description="' . $description . '">';
    echo wp_get_attachment_image($attachment->ID, 'large');
    echo '</div>';
    endforeach;
?>

Answer 1

Use below code

<?php 

    $isFirst = true;

    $i=1;   

    foreach ( $attachments as $attachment ):
    $description = $attachment->post_content;
    if($i==1)
    {
            echo '<div class="item'.$isFirst.'" data-description="' . $description . '">';
            echo wp_get_attachment_image($attachment->ID, 'large');
            echo '</div>';
    }
    else
    {
            echo '<div class="item" data-description="' . $description . '">';
            echo wp_get_attachment_image($attachment->ID, 'large');
            echo '</div>';
    }
        $i++;
      endforeach;
?>